Mould closure device for a pressure moulding machine



O United States Patent 11113 72] Inventor Rene Georges Bachelier [56] References Cited Paris, France UNXTED STATES PATENTS pp 699,227 2,115,590 4/1938 Ryder 18/30(LA) 1 1 Flled 19,1968 2,498,264 2/1950 Goldhard 18/30(LT) 1 Patented Nov-17,1970 2 869 190 1/1959 Schofield 100/272X 73] Assignee Ateliers de Constructions Mecaniques et de l 3,262,158 7/1966 Von Relmer m1. l8/30(LA) Chaudmnnem cmpetLwvet 3,394,434 7/1968 Hart-Still 18/30(LV) La Courneuve, France a corporation f France Primary Exam iner-J Spencer Overholser [32] Priority Jan. 24, 1967 Assistant Examiner-Michael 0. Sutton 33] France Attorney- Young & Thompson [31] No. 92,216

[54] ICE FOR A PRESSURE ABSTRACT: A device for bringing together and locking the two parts ofa two-part mould in a pressure moulding machine 7 Chums 3 Drawmg Flgs in which the mould parts are carried respectively by fixed and [52] US. Cl 164/303; movable plates and in which relative approach of said plates is 18/30: 100/272 effected by at least one jack disposed between the machine [51] lnt.Cl 822d 17/26 frame and movable plate and locking of said parts in their [50} Field ot'Search .v l8/30CK, closed position is effected by a jack controlled toggle 30L(ALL),43, l6T: 164/113. 303: 100/272 mechanism.

Shet

&

Z of 3 Sheet Mmawrme dam [use la 9M 74%..

Patented Nov. 17, 1970 Sheet 19:: Game 0 :5

MOULD CLOSURE DEVICE FOR A PRESSURE MOULDING MACHINE The present invention relates to a mould closure device for a pressure moulding machine, particularly for metals and notably non-ferrous metals.

It is known that in certain of these machines the mould is formed in two parts, one being carried by a fixed plate and the other by a movable plate which latter is moved, in an approach step, towards the fixed plate to bring the two parts of the inould into contact.

In a locking step, the closure device applies the two parts of the mould against each other with a predetermined force and locks them in this position, this closing force being intended, during injection of metal, to compensate for dimensional variations of the mould and to prevent the latter from opening.

The approach step requires a large travel but only a small force, whilst the locking step is carried out over a very short travel and necessitates a large force.

Closure devices have already been proposed which use for the approach step a toggle linkage of the kind usually used in presses, and for the locking step a hydraulically controlled piston. In these devices the impossibility of housing the very long links causes the approach travel to be reduced and consequently limits the height of the mouldable parts, whilst the locking force applied by the piston is limited to a predetermined value so that sure closure cannot be guaranteed when the prescribed working load is exceeded.

In other completely hydraulic devices, the approach movement is obtained by the action of a jack, the locking being effected as previously by a piston. The drawback of uncertain closure remains.

A main object of the present invention is to provide a mould closure device which is free from these various disadvantages.

The closure device according to the invention, adapted, in a pressure moulding machine, to bring together and lock the two parts ofa mould carried respectively by a fixed plate and a movable plate, of the kind comprising approach means to bring the two parts of the mould into contact, and locking means to apply the two parts together and maintain them one against the other with a predetermined force, is characterized particularly in that the approach means comprise at least one approach jack disposed between the machine frame and the movable plate, whilst the locking means comprise a toggle mechanism controlled by ajack.

By virtue of this arrangement the approach travel is, practically speaking, unlimited, and this enables very thick moulds to be used and relatively high moulded parts to be produced, whilst the locking, effected by the toggle mechanism, is particularly sure and powerful.

In order that the invention may be more fully understood, one embodiment in accordance therewith will now be described, by way of example, with reference to the accompanying drawings in which:

FIG. 1 is a side elevation in partial section of one embodiment of the machine of the invention showing the two parts of the mould separated;

FIG. 2 is a similar view to FIG. 1 showing the mould parts separated but the toggle mechanism being in the rest position; and

FIG. 3 is a similar view to the previous ones showing the closure and locking of the mould.

In the embodiment shown in the drawings, the closure device of the invention is mounted on a frame lj'and associated with a fixed plate 11 which carries a part 12 of the mould and is disposed in a vertical plane; the second part 13 of the mould is fixed to a movable plate 14, parallel to the fixed plate, slidably mounted on horizontal guide bearers 15 fixed to the plate 11 and passing through aperture 16 of the movable plate provided with sleeves 17. The plate 14 rests moreover by means of a foot 18 of adjustable height, on a slideway 20 of the frame 10, parallel to the bearers 15.

The frame 10 also carries a large bearing plate or support 22 extending parallel to the plates 11 and 14 and located at the opposite side of the plate 14 to that facing plate 11. The

. bearers 15, of which the end 24 is threaded, pass through the bearing support 22 which rests on slideways 23 of the frame, the position of the support 22 being fixed with respect to the fixed plate 11 by screws 26 screwed on the said bearers.

At least one double-acting hydraulic approach jack 30 is disposed between the bearing support 22 and the movable plate 14, the body 32 of this jack being fixed to the support 22, whilst the piston 33 of the jack is attached by a rod 34 to the movable plate. Two passages 36 and 37 for carrying hydraulic fluid under pressure lead into the jack body 32 to either side of the piston 33, input of fluid through the passage 36 causing displacement of the plate 14 in the direction of the fixed plate 11. Input of fluid through the passage 37 causes relative separation of the two plates. Reference will be made in the following description to a single approach jack, but it will be understood that the closure device may include more than one jack.

Between the bearing support 22 and the movable plate 14 is disposed a supporting plate 40, slidably mounted on the guiding bearers 15. In its central portion, on its side facing the bearing support 22, this supporting plate 40 carries an as sembly of minor bearers 42 forming a support for the body 43 of a control jack 44 extending parallel to the bearers I5 and passing through a central opening 46 in the bearing support 22. This body 43 is supported additionally by a series of rollers 48 resting on rails 49, formed on an extension 50 of the bearing support 22.

In the cylinder of the body 43 is disposed a working piston 52 rigid with an axial rod 53 which extends in the direction of the plate 40 and passes in sealed manner through the corresponding end of the jack. The outer end 54 of the rod 53 is threaded and receives-an internally threaded end piece 56 forming a screw and rigid with a rod 57 forming a prolongation of the screw and passing through a centralopening 58 of the plate 40. The end 60 of the rod 57 has, between the plate 40 and the movable plate 14, a head 61 on which are pivoted, as will be seen hereinafter, the links ofa toggle mechanism 62 connecting the plate 40 and the movable plate plate 14.

In the example described, this mechanism comprises two assemblies of links which are symmetrical with respect to the axis of the rods 53 and 57. Each assembly has a link 64 bent at right angles, hinged at one end on a pivot 65 carried by a tongue 66 of the plate 40, and at its other end, on a pivot 67, to one end ofa link 68 whose other end is hinged by a pivot 69 to the head 61.

The elbow of the link 64 has a pivot 70 acting as a hinge for one endof a link 72 whose other end is hinged about a pivot 73 carried by the movable plate 14. The axes of the pivots 65, 67, 6 9, 70 and 73 are all parallel to one another and perpendicular to the axis of the guide bearers 15 The cylinder 43 of the control jack 44 contains, in addition to the working piston 52, an abutment piston 75 through which passes, through suitable sealed joints, the rod 53. The exterior of the piston skirt has a widened portion 7 6 so that the piston has two end faces 77 and 78 of unequal section. The face 77, having the smallest section, faces the piston 52, and the other face 78 faces the movable plate, its section being greater than the operative section of the working piston 52. The interior of the jack cylinder has a shoulder 80 forming an abutment for the wider portion '76 of the piston when the latter is moved away from the movable plate. The jack cylinder 44 is connected to a source of hydraulic fluid under pressure by three passages 81, 82, 83 leading respectively to the end of the jack in the vicinity of the piston 52, between the pistons 52 and 75 and near the end of the jack facing the movable plate.

By virtue of these arrangements, when fluid under pressure is introduced into the jack through the orifice 83, the abutment piston 75 is pushed towards the piston 52 until it comes into contact with the shoulder 80 which limits its movement.

It is immaterial whether or not fluid is injected through the passage 82 since the section of the piston 78 is the largest and the resulting force is directed towards the piston 52. If, however, fluid is injected through the passage 82 and no fluid is in-- troduced through 81, the'piston 52 occupies an extreme position against the end face of the jack which faces the movable plate. The rods 53 and 57 are thus retracted and the toggle mechanism is in its open position (FIG. 1), the pivots 65, 70 and 73 being disposed at a relatively wide angle of which 70 is the apex.

If fluid is introduced through the passage 81 the piston 52 is moved towards the piston 75 until it abuts against the latter, this being an intermediate or rest position of the piston 52 corresponding to an intermediate position of the toggle mechanism, the pivots 65,70 and '73 being nearly aligned.

Finally, if the pressure is maintained by the passage 81 but cut off at 83, the piston 52 pushes the piston 75 towards the movable plate until the screw 56 abuts against the plate 40 (FIG. 3). The toggle mechanism is then in the locking position, the pivots 65, 70 and 73 being aligned. The operation of this mechanism will be described later.

The plate 40 carries at least one supporting bar 86 parallel to the bearers and directed away from the plates 14 and 11. This supporting bar which passes through an appropriate opening in the bearing support 22 ends in a bearing 87 located in a plane slightly inclined with respect to a plane normal to the axis of the bar 86. This bearing is disposed so as to be directly beneath a compensating wedge pin 88 transversely movable with respect to the bar 86, when the plates 14 and 11 have moved towards each other, the parts 12 and13 of the mould being in contact, and when the toggle mechanism is in its rest position as defined above. The pin 88 is carried by the rod of a double-acting compensation jack 90 having two fluid inlet passages 91 and 92 disposed to either side of its piston, and is arranged so that its inclined face 94 cooperates with the inclined bearing 87 when it is moved towards the latter.

In the following description, reference will be made also to a single compensating jack 90, but it will be understood that the device of the invention can have more than one of these.

The operation of the closure device described above is as follows:

When stopped the mould is open. The hydraulic fluid under pressure arrives bythe passage 83 of the control jack 44 and this maintains the abutment piston 75 in contact with the shoulder 80; this fluid also arrives through the passage 82 and maintains the working piston 52 in its rear position.

The compensation wedge pin 88 is raised, pressure fluid arriving at 92 on the jack 90.

The approach jack 30 is fed at 37 and this maintains the movable plate 14 separated from the fixed plate'll.

This state of the device corresponds to FIG. 1.

In the control jack 44, the arrival of fluid at 82 is interrupted, the fluid being then led in at 81. The working piston 52 comes into contact with the abutment piston 75 which it cannot push back because of the greater sectionof the latter, as was seen above.

The head 61 is moved towards the movable plate and the toggle mechanism, moved towards its locking position, stops in its intermediate rest position defined above (FIG. 2). This position can be adjusted by altering the length of the rods 53 and 57 by operating the screw 56.

At this point the pressure in the approach jack 30 is reversed. The movable plate moves with the toggle mechanism assembly and the part 13 of the mould comes into contact with the part 12 thereof. In this movement, the inclined bearing 87 of the supporting bar 86 comes directly beneath the compensation wedge pin 88. The latter is lowered by injection of fluid under pressure into the jack 90 by the passage 91 and the lowering continues until there is no longer any play between the bearing surfaces 87 and 94. Thus, any variation in thickness of the mould is compensated for by insertion of the wedge pin to a certain depth. The plate 14 cannot move backwards.

The pressure at 83 is then removed. The working piston, still under pressure, pushes back the abutment piston 75 and the head 61 moves towards the movable plate and actuates the toggle links. This continues until the screw 56 comes into contact with the plate 40, this position corresponding to the alignment of the pivots 65, 70 and 73 (FIG. 3). The bearers 15 are thus caused to extend since the plate 14 cannot reverse and the distance separating the extreme pivots 65 and 73 of the toggle linkage is then at its greatest.

The mould is thus locked with a closure force regulated by the final travel of the toggle mechanism from its rest position. This force can therefore be altered by adjusting the length of the rods 53 and 57.

At this stage, injection moulding of the desired part is performed. When the part is cooling a weak force is sufficient to hold the mould closed and this force is provided by the approach jack 30.

Pressure is applied 'at 83 and 82. The piston 75 regains its abutment position and the piston 52 moves back to the bottom of the cylinder causing complete opening of the toggle mechanism. During this movement the distance through which the pivots 65 and '73 move towards each other is therefore greater than the displacement of these pivots which has caused the elongation of the bearers 15 (displacement from the intermediate rest position to the locking position).

The bearing 87 of the supporting bar 86 is thus separated sightly from the wedge pin 88 which can be raised without difficulty by the jack 90.

To open the mould, the approach jack 30 is supplied at 37 and this causes the movable plate 14 to move back.

Advantage can be taken of this opening of the mould to eject the moulded part by virtue of the long travel made possible by the approach jack. It is sufficient, for example, to cause an ejector carried by the movable plate to come into abutment against the bearing support 22 by means of adjustable rods (not shown). The speed of displacement can be regulated at this moment in the cycle. Moreover, if the ejector is to be returned prior to commencement of a new cycle, it is sufficient to reverse once again the movement of the approach jack'30 to move together the two parts of the mould over a length slightly greater than the ejection travel.

This arrangement enables the disadvantages of known toggle type devices to be avoided, since the approach jack 30 enables any desired travel length to be obtained and moreover allows the moulded part to be extracted without the use of an auxiliary jack. In addition, adjustment of the tensile force in the bearers is effected in a single operation by manipulation of a central screw 56 and the tensile force in the bearers, and thus the closure force, remain constant and independent of the influence of expansions of the mould. It is thus possible to install a comparator indicating the tensile force in the bearers and enabling an accurate adjustment of the closure force to be made.

The present invention is not limited to the embodiment described and shown. It remains within the scope of the invention to modify the disposition and number of approach or compensation jacks, as well as of the guide bearers or supporting bars.

In particular, the guide bearers may be vertically disposed. Such an arrangement can be more advantageous in certain applications of the closure'device of the invention, notably when this device forms part of injection transfer and compression moulding machines for plastic materials.

lclaim:

1. In a pressure moulding machine comprising a machine frame, a mould having twoseparable parts, and including afixed member and a movable member on which said two parts are respectively mounted, a mould closure and locking device for bringing said mould parts together and holding them in their closed position under a predetermined force comprising mould closure means and mould locking means, said machine comprising-at least one fluid-pressure operated jack fixed with respect to the machine frame and operatively connected to the movable member and the locking means comprising a toggle mechanism connected to said movable member and actuated by a fluid-pressure operated control jack; the improvement'comprising a supporting member on which the toggle mechanism is mounted, a rod of adjustable length operatively associated at one end with the toggle mechanism, a working piston operatively associated with the other end of said rod and movable in the cylinder of the control jack, an abutment piston movable within said cylinder and having one face of greater section than said working piston, said rod passing freely through an opening in said abutment piston, fluid inlets to said cylinder disposed so as to enable fluid to be applied to either side of each piston in a desired sequence, at least one supporting bar carried by said supporting member, said bar extending away from the fixed member and having an inclined bearing surface, and a wedge pin and actuation cylinder therefor, said pin being disposed so as to be operable by said actuation cylinder to cooperate with said bearing surface when the working piston and toggle mechanism are in an intermediate position defined by abutment of said working piston against said abutment piston, which position is between those in which the mould parts are respectively fully separated and locked, to prevent movement of the movable member towards its mould opening position.

2. An assembly according to claim 1, characterized in that said fluid inlets are so arranged as to enable said toggle mechanism to be moved successively into said intermediate position, and, after actuation of the closure jack, and actuation of said pin to cooperate with said bearing surface, into its locking position.

3. An assemblyaccording to claim 1, characterized in that the two end facesof the abutment piston have unequal sections, the greatest section being that furthest removed from the working piston and being greater than the operative section of said working piston.

4. An assembly according to claim 1, characterized in that said rod carries an adjustable abutment which by contact with said supporting member defines the locking position of the toggle mechanism.

' 5. An assembly according to claim 1, characterized in that said support member is substantially vertically disposed and I carried by a bearing support mounted for horizontal adjustporting member by horizontal tie rods, and supported at its other end on rollers engaging a horizontal track formed on an extension of said bearing support. 

